<?php

/**
 * @file
 * Defines a field storage backend.
 */


/**
 * Implements hook_field_storage_info().
 */
function field_test_field_storage_info() {
	return array(
			'field_test_storage' => array(
					'label' => t('Test storage'),
					'description' => t('Dummy test storage backend. Stores field values in the variable table.'),
			),
			'field_test_storage_failure' => array(
					'label' => t('Test storage failure'),
					'description' => t('Dummy test storage backend. Always fails to create fields.'),
			),
	);
}

/**
 * Implements hook_field_storage_details().
 */
function field_test_field_storage_details($field) {
	$details = array();

	// Add field columns.
	$columns = array();
	foreach ((array) $field['columns'] as $column_name => $attributes) {
		$columns[$column_name] = $column_name;
	}
	return array(
			'drupal_variables' => array(
					'field_test_storage_data[FIELD_LOAD_CURRENT]' => $columns,
					'field_test_storage_data[FIELD_LOAD_REVISION]' => $columns,
			),
	);
}

/**
 * Implements hook_field_storage_details_alter().
 *
 * @see FieldAttachStorageTestCase::testFieldStorageDetailsAlter()
 */
function field_test_field_storage_details_alter(&$details, $field) {

	// For testing, storage details are changed only because of the field name.
	if ($field['field_name'] == 'field_test_change_my_details') {
		$columns = array();
		foreach ((array) $field['columns'] as $column_name => $attributes) {
			$columns[$column_name] = $column_name;
		}
		$details['drupal_variables'] = array(
				FIELD_LOAD_CURRENT => array(
						'moon' => $columns,
				),
				FIELD_LOAD_REVISION => array(
						'mars' => $columns,
				),
		);
	}
}

/**
 * Helper function: stores or retrieves data from the 'storage backend'.
 */
function _field_test_storage_data($data = NULL) {
	if (!isset($data)) {
		return variable_get('field_test_storage_data', array());
	}
	else {
		variable_set('field_test_storage_data', $data);
	}
}

/**
 * Implements hook_field_storage_load().
 */
function field_test_field_storage_load($entity_type, $entities, $age, $fields, $options) {
	$data = _field_test_storage_data();

	$load_current = $age == FIELD_LOAD_CURRENT;

	foreach ($fields as $field_id => $ids) {
		$field = field_info_field_by_id($field_id);
		$field_name = $field['field_name'];
		$field_data = $data[$field['id']];
		$sub_table = $load_current ? 'current' : 'revisions';
		$delta_count = array();
		foreach ($field_data[$sub_table] as $row) {
			if ($row->type == $entity_type && (!$row->deleted || $options['deleted'])) {
				if (($load_current && in_array($row->entity_id, $ids)) || (!$load_current && in_array($row->revision_id, $ids))) {
					if (in_array($row->language, field_available_languages($entity_type, $field))) {
						if (!isset($delta_count[$row->entity_id][$row->language])) {
							$delta_count[$row->entity_id][$row->language] = 0;
						}
						if ($field['cardinality'] == FIELD_CARDINALITY_UNLIMITED || $delta_count[$row->entity_id][$row->language] < $field['cardinality']) {
							$item = array();
							foreach ($field['columns'] as $column => $attributes) {
								$item[$column] = $row->{$column};
							}
							$entities[$row->entity_id]->{$field_name}[$row->language][] = $item;
							$delta_count[$row->entity_id][$row->language]++;
						}
					}
				}
			}
		}
	}
}

/**
 * Implements hook_field_storage_write().
 */
function field_test_field_storage_write($entity_type, $entity, $op, $fields) {
	$data = _field_test_storage_data();

	list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);

	foreach ($fields as $field_id) {
		$field = field_info_field_by_id($field_id);
		$field_name = $field['field_name'];
		$field_data = &$data[$field_id];

		$all_languages = field_available_languages($entity_type, $field);
		$field_languages = array_intersect($all_languages, array_keys((array) $entity->$field_name));

		// Delete and insert, rather than update, in case a value was added.
		if ($op == FIELD_STORAGE_UPDATE) {
			// Delete languages present in the incoming $entity->$field_name.
			// Delete all languages if $entity->$field_name is empty.
			$languages = !empty($entity->$field_name) ? $field_languages : $all_languages;
			if ($languages) {
				foreach ($field_data['current'] as $key => $row) {
					if ($row->type == $entity_type && $row->entity_id == $id && in_array($row->language, $languages)) {
						unset($field_data['current'][$key]);
					}
				}
				if (isset($vid)) {
					foreach ($field_data['revisions'] as $key => $row) {
						if ($row->type == $entity_type && $row->revision_id == $vid) {
							unset($field_data['revisions'][$key]);
						}
					}
				}
			}
		}

		foreach ($field_languages as $langcode) {
			$items = (array) $entity->{$field_name}[$langcode];
			$delta_count = 0;
			foreach ($items as $delta => $item) {
				$row = (object) array(
						'field_id' => $field_id,
						'type' => $entity_type,
						'entity_id' => $id,
						'revision_id' => $vid,
						'bundle' => $bundle,
						'delta' => $delta,
						'deleted' => FALSE,
						'language' => $langcode,
				);
				foreach ($field['columns'] as $column => $attributes) {
					$row->{$column} = isset($item[$column]) ? $item[$column] : NULL;
				}

				$field_data['current'][] = $row;
				if (isset($vid)) {
					$field_data['revisions'][] = $row;
				}

				if ($field['cardinality'] != FIELD_CARDINALITY_UNLIMITED && ++$delta_count == $field['cardinality']) {
					break;
				}
			}
		}
	}

	_field_test_storage_data($data);
}

/**
 * Implements hook_field_storage_delete().
 */
function field_test_field_storage_delete($entity_type, $entity, $fields) {
	list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);

	// Note: reusing field_test_storage_purge(), like field_sql_storage.module
	// does, is highly inefficient in our case...
	foreach (field_info_instances($bundle) as $instance) {
		if (isset($fields[$instance['field_id']])) {
			$field = field_info_field_by_id($instance['field_id']);
			field_test_field_storage_purge($entity_type, $entity, $field, $instance);
		}
	}
}

/**
 * Implements hook_field_storage_purge().
 */
function field_test_field_storage_purge($entity_type, $entity, $field, $instance) {
	$data = _field_test_storage_data();

	list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);

	$field_data = &$data[$field['id']];
	foreach (array('current', 'revisions') as $sub_table) {
		foreach ($field_data[$sub_table] as $key => $row) {
			if ($row->type == $entity_type && $row->entity_id == $id) {
				unset($field_data[$sub_table][$key]);
			}
		}
	}

	_field_test_storage_data($data);
}

/**
 * Implements hook_field_storage_delete_revision().
 */
function field_test_field_storage_delete_revision($entity_type, $entity, $fields) {
	$data = _field_test_storage_data();

	list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);
	foreach ($fields as $field_id) {
		$field_data = &$data[$field_id];
		foreach (array('current', 'revisions') as $sub_table) {
			foreach ($field_data[$sub_table] as $key => $row) {
				if ($row->type == $entity_type && $row->entity_id == $id && $row->revision_id == $vid) {
					unset($field_data[$sub_table][$key]);
				}
			}
		}
	}

	_field_test_storage_data($data);
}

/**
 * Implements hook_field_storage_query().
 */
function field_test_field_storage_query($field_id, $conditions, $count, &$cursor = NULL, $age) {
	$data = _field_test_storage_data();

	$load_current = $age == FIELD_LOAD_CURRENT;

	$field = field_info_field_by_id($field_id);
	$field_columns = array_keys($field['columns']);

	$field_data = $data[$field['id']];
	$sub_table = $load_current ? 'current' : 'revisions';
	// We need to sort records by entity type and entity id.
	usort($field_data[$sub_table], '_field_test_field_storage_query_sort_helper');

	// Initialize results array.
	$return = array();
	$entity_count = 0;
	$rows_count = 0;
	$rows_total = count($field_data[$sub_table]);
	$skip = $cursor;
	$skipped = 0;

	foreach ($field_data[$sub_table] as $row) {
		if ($count != FIELD_QUERY_NO_LIMIT && $entity_count >= $count) {
			break;
		}

		if ($row->field_id == $field['id']) {
			$match = TRUE;
			$condition_deleted = FALSE;
			// Add conditions.
			foreach ($conditions as $condition) {
				@list($column, $value, $operator) = $condition;
				if (empty($operator)) {
					$operator = is_array($value) ? 'IN' : '=';
				}
				switch ($operator) {
					case '=':
						$match = $match && $row->{$column} == $value;
						break;
					case '<>':
					case '<':
					case '<=':
					case '>':
					case '>=':
						eval('$match = $match && ' . $row->{$column} . ' ' . $operator . ' '. $value);
						break;
					case 'IN':
						$match = $match && in_array($row->{$column}, $value);
						break;
					case 'NOT IN':
						$match = $match && !in_array($row->{$column}, $value);
						break;
					case 'BETWEEN':
						$match = $match && $row->{$column} >= $value[0] && $row->{$column} <= $value[1];
						break;
					case 'STARTS_WITH':
					case 'ENDS_WITH':
					case 'CONTAINS':
						// Not supported.
						$match = FALSE;
						break;
				}
				// Track condition on 'deleted'.
				if ($column == 'deleted') {
					$condition_deleted = TRUE;
				}
			}

			// Exclude deleted data unless we have a condition on it.
			if (!$condition_deleted && $row->deleted) {
				$match = FALSE;
			}

			if ($match) {
				if (!isset($skip) || $skipped >= $skip) {
					$cursor++;
					// If querying all revisions and the entity type has revisions, we need
					// to key the results by revision_ids.
					$entity_type = entity_get_info($row->type);
					$id = ($load_current || empty($entity_type['entity keys']['revision'])) ? $row->entity_id : $row->revision_id;

					if (!isset($return[$row->type][$id])) {
						$return[$row->type][$id] = entity_create_stub_entity($row->type, array($row->entity_id, $row->revision_id, $row->bundle));
						$entity_count++;
					}
				}
				else {
					$skipped++;
				}
			}
		}
		$rows_count++;

		// The query is complete if we walked the whole array.
		if ($count != FIELD_QUERY_NO_LIMIT && $rows_count >= $rows_total) {
			$cursor = FIELD_QUERY_COMPLETE;
		}
	}

	return $return;
}

/**
 * Sort helper for field_test_field_storage_query().
 *
 * Sorts by entity type and entity id.
 */
function _field_test_field_storage_query_sort_helper($a, $b) {
	if ($a->type == $b->type) {
		if ($a->entity_id == $b->entity_id) {
			return 0;
		}
		else {
			return $a->entity_id < $b->entity_id ? -1 : 1;
		}
	}
	else {
		return $a->type < $b->type ? -1 : 1;
	}
}

/**
 * Implements hook_field_storage_create_field().
 */
function field_test_field_storage_create_field($field) {
	if ($field['storage']['type'] == 'field_test_storage_failure') {
		throw new Exception('field_test_storage_failure engine always fails to create fields');
	}

	$data = _field_test_storage_data();

	$data[$field['id']] = array(
			'current' => array(),
			'revisions' => array(),
	);

	_field_test_storage_data($data);
}

/**
 * Implements hook_field_storage_delete_field().
 */
function field_test_field_storage_delete_field($field) {
	$data = _field_test_storage_data();

	$field_data = &$data[$field['id']];
	foreach (array('current', 'revisions') as $sub_table) {
		foreach ($field_data[$sub_table] as &$row) {
			$row->deleted = TRUE;
		}
	}

	_field_test_storage_data($data);
}

/**
 * Implements hook_field_storage_delete_instance().
 */
function field_test_field_storage_delete_instance($instance) {
	$data = _field_test_storage_data();

	$field = field_info_field($instance['field_name']);
	$field_data = &$data[$field['id']];
	foreach (array('current', 'revisions') as $sub_table) {
		foreach ($field_data[$sub_table] as &$row) {
			if ($row->bundle == $instance['bundle']) {
				$row->deleted = TRUE;
			}
		}
	}

	_field_test_storage_data($data);
}

/**
 * Implements hook_field_attach_create_bundle().
 */
function field_test_field_attach_create_bundle($bundle) {
	// We don't need to do anything here.
}

/**
 * Implements hook_field_attach_rename_bundle().
 */
function field_test_field_attach_rename_bundle($bundle_old, $bundle_new) {
	$data = _field_test_storage_data();

	// We need to account for deleted or inactive fields and instances.
	$instances = field_read_instances(array('bundle' => $bundle_new), array('include_deleted' => TRUE, 'include_inactive' => TRUE));
	foreach ($instances as $field_name => $instance) {
		$field = field_info_field_by_id($instance['field_id']);
		if ($field['storage']['type'] == 'field_test_storage') {
			$field_data = &$data[$field['id']];
			foreach (array('current', 'revisions') as $sub_table) {
				foreach ($field_data[$sub_table] as &$row) {
					if ($row->bundle == $bundle_old) {
						$row->bundle = $bundle_new;
					}
				}
			}
		}
	}

	_field_test_storage_data($data);
}

/**
 * Implements hook_field_attach_delete_bundle().
 */
function field_test_field_attach_delete_bundle($entity_type, $bundle, $instances) {
	$data = _field_test_storage_data();

	foreach ($instances as $field_name => $instance) {
		$field = field_info_field($field_name);
		if ($field['storage']['type'] == 'field_test_storage') {
			$field_data = &$data[$field['id']];
			foreach (array('current', 'revisions') as $sub_table) {
				foreach ($field_data[$sub_table] as &$row) {
					if ($row->bundle == $bundle_old) {
						$row->deleted = TRUE;
					}
				}
			}
		}
	}

	_field_test_storage_data($data);
}
